This is a mod for Patrick's Parabox, to allow support for custom hub areas to be created. Using it is a little complicated, so feel free to DM me if I haven't made something clear enough here.
To install this mod, first locate the parabox game files. These are usually found at "C:\Program Files (x86)\Steam\steamapps\common\Patrick's Parabox". Install BepInEx into this folder, by following the instructions in the BepInEx documentation. (On Windows, the correct version depends on whether you have a 32 bit or 64 bit computer.) Download the file "CustomHubs.dll" from the releases page of this repository, and move it into the folder "Patrick's Parabox\BepInEx\plugins", which should already have been generated.
You can now load custom hubs, by moving them into your custom level folder and loading them as normal.
One point before I begin: I have generally taken the approach of not patching bugs that were in the main game to start with. This can lead to janky interactions if you do anything unusual.
If you didn't understand any of this explanation, a complete example called test_hub is given in this repository.
The most important file (and technically the only required file) is the map file for the hub, which should be called hub.txt. The format is mostly the same as a custom level, but with a few changes. The hub file allows the use of portals, which have the following syntax:
Floor x y Portal puzzle_name
References have a slightly different syntax to normal, since they have an additional argument at the end, giving the name of the area they are pointing to. Every area should have at least one reference to it, otherwise the game will not know which area it is.
In addition, walls also have an extra argument, with the following effects:
_: a regular wall.- the name of a puzzle: indicates this wall will unlock when enough puzzles are complete, and it should be connected to the named puzzle.
*clear: unlocks when the player has seen the credits.*clear_or_unlock_all: as above, but also unlocks if the "unlock all puzzles" setting is activated.*all: unlocks when all puzzles are complete.
The required number of puzzles to unlock a wall connected to a puzzle is the number of main line puzzles in the area. (In the main game, this is also true for most areas, but Wall and Swap are hardcoded to have a different number of puzzles required.)
Finally, a playerButton will launch the credits sequence, if unlocked.
The mechanics for deciding when a level is unlocked are complicated. If a puzzle has any lines going to it from other puzzles, the first of which is complete, then the puzzle is unlocked. In addition, if an area is not within another area, or the space above it is empty (or an unlocked wall) some of the puzzles in it are automatically unlocked. This works in a way that is mostly easy to understand, but it should be noted that blue bonus levels with no lines going to them only unlock when all unlockable walls in the area (ie walls with something other than _ as their extra argument) are unlocked.
There are a few more important points to bear in mind. Firstly, the player should not start next to a portal, since this interferes with the way the portal is exited. Secondly, when reloading a save, the player will be placed on the center of the second row from the top in the current area, so this spot should be kept clear in every area.
All other files can be placed in subdirectories if you choose, which you may find useful for organising levels. In addition, most of the required data can be split across multiple files and placed in different directories if needed - two files named "area_data.txt" in different subdirectories will be treated as if they were concatenated.
Each puzzle should be given a level file called "{name_of_puzzle}.txt". This can be any normal custom level, with one exception - custom_level_music must be set, to something other than -1. There should also be an image file, eg "{name_of_puzzle}.png", indicating what should be displayed on the portal. If you don't provide an image, one will be generated for you.
The file "area_data.txt" should have an entry for every area of the hub. Each line has the format:
area_name music
where music indicates the id of the music for that area (again, this cannot be -1).
The file "puzzle_data.txt" is more complex. There should be a line for every puzzle, with the format:
puzzle_name hard eyesJump referenceName
hard should be 0 for main-line levels, 1 for challenge levels, and 2 for special levels. eyesJump indicates whether the player should possess the portal rather than jumping into it. referenceName indicates the number of the level.
Another file, "puzzle_lines.txt", indicates which puzzles are connected to each other. The format is:
from to immediate
if the line goes from the puzzle called from to the puzzle to. immediate indicates whether completing from immediately takes you to to.
The only remaining file is "credits.txt", an optional file indicating what credits will play if you complete the hub.